Ruth Heathcock (nee Rayney) was a South Australian nurse who worked with Aboriginal people suffering from leprosy in the Roper River and Gulf Country of the Northern Territory from 1930 to 1942. In treating their leprosy, she enabled her patients to continue living in their country and escape incarceration, which was usually for life, on the Channel Island lazaret off the coast of Darwin. Ruth demonstrated that she respected Aboriginal law above the recently imposed minority white laws that had resulted from colonisation, in spite of the fact that her husband was an official enforcer of those laws. A Northern Territory mounted constable, he was invested, as were all policemen in the Territory after 1920, with the power of Aboriginal 'protector'. Ted Heathcock, however, was won over by Ruth and turned what she referred to as a 'blind eye' to the work she practised for over a decade while he was absent on patrols for up to six months at a time. Eventually Ruth and Ted campaigned for a repeal of the Northern Territory Administration's Ordinance for the Suppression of Leprosy 1928, under which 'leprosy suspects' were detained. Ruth was well known as a skillful and courageous nurse and was awarded an MBE in 1951 for her bravery and initiative in the attempted rescue at Manangoora of wounded bushman Horace Foster. This involved travelling for more than 180 kilometres during the height of the monsoon season, through flooded rivers and the open sea, in a dugout canoe with four others. She used the occasion, however, to make known the seminal role of Aboriginal people in the rescue 'without whom,' she maintained, 'I couldn't even have existed.' This essay focuses on Ruth Heathcock's work with leprosy during her period in Arnhem Land, and the critical role of Aboriginal women domestic workers in shaping the philosophy behind her professional activism. Her work was profoundly influenced by her lived experiences, including her socialisation as a child in the first two decades of the 20th century in the lower Murray region of South Australia. In her personal writings and interactions with non-Indigenous people, Ruth advanced the idea of Aboriginal women's autonomy, expert knowledges and ritual career status, which at the time were given little credence in either the popular imagination or the anthropological arena. Her participation in Aboriginal women's complex religious and spiritual life during her time at Roper River encouraged Ruth's later exploration of alternative areas of spirituality. Much in Ruth's story has remained silent in all these years because of the clandestine nature of her work. Vic Hall's 1968 biography, Sister Ruth, limited by romanticism and the novelistic genre, suggests the need for a fresh exploration of this narrative in the light of current debates surrounding gender and cross-cultural friendships, and black-white relations from the 1930s to the early 1940s. Rich source material exists within the oral traditions of presentday Roper River community historians based at Ngukurr. Ruth Heathcock's presence continues to be memorialised there and her narrative is understood as an important historical signifier of crosscultural relations that were outstandingly different to the dominant. Research for this chapter has evolved from new material recorded with the descendants of the house workers and other Indigenous historians within the Ngukurr, Numbulwar and Borroloola communities; from government records and archival sources; and from extensive conversations I had with Ruth Heathcock in Adelaide during the 1980s.